1. Field of the Invention
The present invention relates to databases. More specifically, the present invention relates to a method and an apparatus for performing multi-stage table updates.
2. Related Art
Many organizations store vast amounts of data in database systems. In order to effectively maintain the integrity of the stored data, many of these databases adhere to a transaction model. As queries are performed against these databases, the manipulation of the data by the query is not visible to the outside world until the transaction encompassing the queries is committed. This allows any data manipulated during the transaction to be rolled-back to the original state if any of the queries fail.
In order to implement these transactions, transactional databases typically require a large amount of space dedicated to transaction logs. These transaction logs may reside in memory or in temporary storage until the transaction is committed. When the transaction is committed the changes in the transaction log are committed to the corresponding datafile. In the case of table-wide updates to large tables, the volume of temporary transaction logs may take up huge amount of memory or disk space.